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R. E. HELLMUND. SYSTEM OF CONTROL. APFLICATI'ON FILED MAY 3, I916.

,32L523. Patented Nov. 11, 1919.

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- ATYTOXRNEY R. El HELLMUND. I SYSTEM OF CONTROL.

APPLICATION HLED MAY 3, I916- Patented Nov. 11, 1919.

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ATTORNEY To all whom it may concern S ES. PATENT omen.

RUDOLF E. HELL UNn-or rrr-rsncxen,lmnnsrnvanm, ASSIGNOR To w as'r- PENNSYLVANIA.

Be it knowntliatI, Runonr E. HELLMUND,

a subjec-tlof the Emperor of Germany, and

a resident of Pittsburgh, in the count of .Allcgheny and State of Pennsylvania, iave invented a new and useful Iiiiprovenientin y I S Of Control, which the following is a specification. r

My invention relates to" apparatus. and

systems of distributionparticularly adapted it; valternatingaziii'teiit railway and it has for anobject to provide a motor, 'to-' 'gether'witli suitable control and supply ap-- paratii's, :whereby' a vehiclefimay be accelerated in a smooth and uniform manner. A- furtlicr ob]ect is to adapt said'motoi" and control apparatus for recupcrative opera:

. tion, with a minimum amount of additional alternating-clir'rent not oi' of the COHHIIU-W auxiliaryapparatus. In the accompanyin drawing, Figure 1 'isa di'agraininatic view of a single-phase,

tutor type, tpgetheiyivit-h its supply and 'coiiti'ol circuits, constructm'l in accordance armature con'ductoisby a cross or indiicing field winding, l)1'( )"l(lfi(l suitable short-cir-.

i f done,-for example, in the \Vinter-Eichberg fields of the clia'racteifldescribed in a manner to achieve new and valuable results, aswill .with my invention Fig.- 2 is a sequence chart-. llustratiiig the method of opei'ation of the switches in Fig.1 during-both geiiei ator-and motor operation: Figs. 2%))", 2"

illustrating the various c nin aetion of the system of Fig-p11; Fig. 3 is a diagran'iinatic view ofa modification 30f the system shown.

iiiatic views sliowing,'iiiorc in detail, the

different control steps 'inthe system of F i 3. P p

h. a i a In the ordinary siii'gleml-iase, alternating current commutator machine, it s customai"y to establish a main or exciting field by, the ,ilC-tlOli of a stator windnig but it '15 well' known that a similar fieldinay be es tablished by currents induced in certain cuiting brushes are properly located, as is motor. By my invention, I-inake use of hereinafter more 'fully appear.

natin -"current railway systems, it is .eus-

INGI IOUSE ELECTRIC 'AND MA NUFACTUB I NG COMPANY,'A CORPORATION OF SYSTEM OF CONTROL.

1916. seriai-nastpu.

toniary to employ motors of the compein sated, commutator type, the exciting field Specification of Letters r tain. .p t a N0 11 .1919 Application filed May},

winding being-connected in .series'with the armature and impartin to the motor a series operating characteristic. Wlien,'ho'w-.

for: example, .Wllell descending grades or decelerating, a motor of the character described is inapplicable because of improper excitation. It has been proposed, as shown, for example, in U. Salaten't No; 977,641, granted Dec. (5, 1910,, tofthe \Vcstinghouse Electric 1% Manufacturing Company, on an ever, ,it is desired to recuperate energy, as,

'application' filed by B. .G. Laniine, to 'pro- 'yi(le-aiixili:i i-y phase shifting apparatus. for

V the proper excitation of the. motor field wmchngs dni-ing .rccuperati've operation. lir-niy'co 'iending application, Serial No.

19,459, filed April (3,1915, I describe a' sys-j tein the same general character as that shown in the aforementioned patent, said system employ ng an auxiliaryphase-converting machineJen'iploying fields of the above described armature or. \Vinter-Eichberg type. r

In the present system, I do, away with auxiliary phase shifting orconverting ap-.

motor oriia-uperative operation directly from' th'e vehicle motors themselves.

"-ln inv copcuding application, Serial No.

(mme, int-(into. 1-4, 191.11 disclose and paratusand am enabled to obtain either and 2 are simplified diagran'miatic views- 'tion, Inot only develop exciting ampereturns in the armature winding, but -I-also produce exciting ampere-turns in an appropriate statorwindn' g: By additive and new-motive forces, an extremelywide and effective control of the resultant exciting field flux is obtained.

- fed connection. Inthe giresentapplication,r the motoris started by. '1'ep iilsion operation In the operation of single-phase,walter-' and then shifted-to doublysfed connections v for intermediate speeds. still higher subtractive combination of said tiivo,inag-- speeds, a pdi tion of the exciting magneto motive force is produced in the armature and a portion 1n the exciting field win'ding,

and finally, at maximum speed, theexciting field is produced entirelywithin the armat ture, producing a shuntv characteristic for preventing overspeeds' and improving the power factor.

*Beferring, to the accompanying drawing for a more detailed understanding of my invention, I show a motor of the singlephase, compensated, commutator type at 27 in V 1, .said motor being provided with an armature 28,-a cross field winding 29 and an exciting "field winding-30. A pair of brushes 31'31 bear upon the commutator in line with the cross-field winding 29 and a similar pair of brushes 3232 bearupon the commutator 1n line with the winding 30. The motor 27 may drive or. be

gdrivenby an axle 9 or other load means.

"the cross-field winding 29 being connected across a portion of the source 33, the brushes 3131 and the brushes 32 32 being respectively connected together in a closed circuit, and the exciting field winding 30 being eliminated from the circuit. v A).

(Position Under these conditions, recuperation is effected exactly as described in my. application Serial No.-66,726, the cutting of the flux of the field 29 by the armature conductors under the brushes 31 establishing,

current flow through'the brushes 3232 and setting up an exciting field within the armature winding itself. Said exciting field, as

explained in a'pplication'No. 66,726, may

be adjusted in phase and in magnitude t?) induce an .electromotive force in the armature conductors under the, brushes 32 32 suitable for theinductiorizOf an FQ in the winding 29 which maybe superposed upon the M. F. of the source 33for reuperative operation.-

For recuperation at. other speeds, the switch 4 is opened and the switch 6 closed,

- whereby the main ficld stator winding is connected in series with the brushes .32.32 and 'a resultant exciting field flux is established in said stator winding. (Position B) Furthermore, the inclusion of said Winding 30. increases the reactance of the ex'citin field supply circuit and, hence, provides more suitable phase relation in the output E. M. F-. for supe position.upon-the line E. M. F., as explained in the companion-application. If, with the last described recuperative connection, it is desired to operate at higher speeds than with the first de scribed recuperative connection, it is essential for proper control of the output E. M. F. that the resultant exciting field be weakened and, accordingly, the exciting field winding 30 is connectedto oppose the exciting field produced within the armature winding, although the latter field must necessarily preponderate at all -times for recuperative I operation. (Position (1). On the other hand, for low speed recuperation, where an exciting field of great strength is necessary 'for the production of proper E. M. F., the field winding 30'is connected to assist the exciting field produced within the armature. Referring-to the form of my invention shown in Fig. 3, which is better adapted for commerclal installation and operation than that shown in Fig.1, a motor of the same. general type is shown at 27, said motor comprising an armature 28, cross-field winding 29, exciting field winding 30,

brushes 31 31, 32-32 and a source 33, all

as in the system of Fig.1. The voltage applied to the outer terminal of the cross-field winding 29 may be adjusted by suitable switches '15, 16 and 17 and a preventive resistor 34, and, in like manner, the voltage applied to an intermediate tap 35 may be adjusted by switches 12, 13 and 14 and a resistor 36. The brushes 31-31 may 'be connected together by a switch 21 or the right hand brush may be connected to a point in the source, either directly through switches 11 and 18' or through a resistor 37, The left hand brush 31 may be connected, at the same time, to the intermediate tap 35 through a switch 20 for impressing a vol tage across the brushes 31-31, and the main .field winding 30 may be connected in series with the cross-field winding 29, either directly through switches 25 and 2G or through a cun'ent-linliting resistor 38. The brushes 3232 may be closed directly upon themselves by a switch 23 or varying amounts of resistance and reactance may be inserted in the circuit therebetween by the manipulation of switches 22 and 24, of a resistor 39 and of a choke coil -10.

Having thus described the arrangement of a system constructed in accordance with .'-my invention, the-operation is as follows: Referring to the first generating position in Fig. 4: and to Fig. 5 for the recuperative connections athigh speed, the 'exciti g and cross-field stator windings are connected in 1 series relation across one-half the sou"ce.33, and the brushes 31-31 are'connected cross the remainder of said source. The brushes 3232 are connected together through the entire choke coil 40. Under .these conditions, the exciting magneto-motive fOrce produced y. I c y y citingmagneto-motive force produced with- 5 in the armature, and the resultant extremely weak a'rlnature exciting fieldis suited for the pr(')d uction of the. desired recuperative E. M. .1 1, at theliighspeed in question.

The flow of load current-to the source; energizesthe excitingfield stator winding with a magneto-motive forcelagging substa1'1tially"180"behind the E. F. of the source, and the load current magneto-mot1ve forceof the stator inducing Winding vectoriallycombines wlth t'he armature cross field magneto-motive force to provide a .r'e=- sultant'eross field magneto-'inotive-force la ging' substantially 90 behindthe E. M.

of the source.

Passing to the next lowerspeed, connec tions for which are shown in Fig. 5", the

intermediate tap 35 isshifted to the right by the manipulation of switches 12, 13 and 14, as indicated in generator positions-2, 3

and 7 As a result, theexcitation of the cross-field wind 'ing .29 is'strengthened and nection 'to the brushes 31- 31, indicated.

n F 1g. 5 and generating position 5, andthc motive force ina greater ratio than the increase :in the, stator exciting field magneto- .rnotire forcein the winding 30, "As a result, there ls'a net gain in excltlng field flux suitable for the production of the (lQS11G(lrecuperative E- in question.

For a still resistor 37 is inserted in the supply con- M. F. atthe-reduced speed neut 'alizing armature cross fieldmagnetomotive force is still '-furtherreduced, produeing an increase in 'thestator cross-field magneto-motive force and, consequently, in

the net a'rl nature exciting field magneto motive force. I.*ig-.'-5' indicates the connections for-a still greater reduction in speed," ,the mid-tap havlng been removed,- thev brusl1es 31.31 being connected together in 'closed circuit and the resistor 37 having been eliminated, as, indicated in generator positions 6 "and 7 As a result, the-full volt-.-

age of the source 33 is impressed across the windings 29 and 30, anda stronger exciting field results than in the preceding cases. H1 Fig. I the outer teri'ninal -o-i .the cross field. winding 29 is shown n' u iv ed inwardly, thus reducing the supply ,vpltagc which mustln-..o\err(nne to effect rerl-um'ation, said result being obtained by the manipi llation of the; switches 15, lG'an'd 17, asindicated in generating positions '8, f) and 10. For the final low-speed recuperatire. position, shown in Fig. 5- said speed being slightly above 'synchronism, and prod need by .the nulnl pul i1 ti0n of the switches 22, 23 and 2.4,the rethe winding 30 nearly neutralizes the e'x-f and a Y further reduction in speed, the

actance between the brushes 32-}32is' grad uall-y eliminated until said brushes are short circuiteduponthemselves, thus permitting" an increase in the exciting field-supply current-flowing Within the arn'iature Winding exciting field; fl ux and of the net exciting For .under-synchronous recuperation it is nea'essaryto establish reverse doubly-fed connections, as described in my copending. application, Serial No. 119,265, filed Sept. 9, 1910,.

By; thus operating, a machine during recuperation, a negative or drooping coinpound characteristic is imparted thereto, asis desirable for recuperative operation, an

increase in" load causing a slight reduction in voltage-and the vice versa,th'us maintainin}; a substantially constant recuperative effect. 0 l

For motor operation, the machine 27 is first connectedibr repulsion action as indicatedv in Fig-s. 5*, 5" and 5 and-in motoring positions 'l'to i, inclusive. Af change -is then made to the 'Well known doubly-fed connection, as shown in Figs. 5 and 5 and in motoring positions?) tollO, inclusivel For afurther increase in speed, the. brushes 32-32 are introduced into" service andare connected. together through ,thechoke coil A0,. as indicated in Fig. 5 and in motoring position 11. :An exciting field is thus estab- -lished inv the arlnature winding which sists the exciting field winding 30 and pro-- duces -a co1'npou1rd operating characteristic conseqi-lent increase in the armature in the motor, theficld- Winding 30 being 'enas a series winding, whereas, the armatureexciting hold is derived from the crossfield' In Fig. 5 the choke dicated in motoring positions 19., 18 and 14 and, hence, the ai'n'lature exciting field Strength is im-reased. position,- shown in Fig. 5, the stator excitergized by loadcurrentand hence operating 7 For the final motor ing field winding 3%) is entirely eliminated and the entire exciting flux .is produced.

within the armature itself, whereby the motor given a shunt operating characteristic, and excessive speeds are prevented.

'lhroughout his a 'iplication. 'I' have' re- Teri-ed to the brushes as being located-in almeuumt w th, .or in quadrature to, the

cross field winding. lt-u'ill-l'm understood -t hat, by said e'.\'pressi'on, lrei'er lo brushes vwhich are in eleeirical"connection with urmaturei-(m durtors in the. respective positions and, hence, the eflect of the throw of the armature coils. in mecliaui tally displacin tlwln'uslu-s, should be disregarded. l1.

3 not new sary, however, for the brushes to be in alinement with the respective fields for successful operation, neither need the two pairs of brushes have a quadrature relation to each other, said conditions being those for maximum effectiveness of operation. Any displacement of the brushes from said position of maximum effectiveness merely renders inactive the armature conductors over certain portions of the armature surface. Furthermore, it is not nec essary to employ four brushes as, by properly, locating three interconnected brushes, a like effect may be obtained, exciting field current passing between two of said brushes, and cross field current passing between one or both of said exciting field brushes and the remaining brush.

While I have shown my invention in its preferred forms, it will be obvious to those' skilled in'the art that it issusceptible of various minor' changes and modifications Without departing from the spirit thereof and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or are indicated in the appended claims.

I claim as my invention:

1. The combination with a source of alternating current, of a dynamo-electric machine comprising a cross-field winding and an exciting field winding, a plurality of brushes arranged to establish armature working circuits and armature exciting circuits, variable-speed driving means for said machine, connections whereby the cross-field winding may be connected across a portion .of the source and the armature working circuit across a portion of the source, means whereby the exciting field may be inserted into one of said circuits, and means whereby the armature exciting circuit may be closed circuited across an external current-limit ing device.

2. The combination with source of alternating current, of a dynamo-electric machine of the cross-field, commutator type having an exciting field winding, variablespeed drivingmeans therefor, a pair of brushes substantiallyin line with the exciting field winding, an additional pair of brushes substantially in line with the crossfield winding, and connections whereby the exciting and cross-field windings of said machinemay be connected to receive energy from said source, the pair of brushes in alinement with the cross-field winding connected across a portion'of said source, and the brushes in alinement with the exciting field winding connected together through a current-limiting device.

3. The combination with a source of alternating current, of a dynamo-electric inachine of the cross-field, commutator type having an exciting field winding, variablespeed drivingmeans therefor,v a pair of brushes substantially in line with the main field winding, an additional pair of brushes substantially in line with the cross field winding, and connections whereby the exciting and cross-field windings of said machine may be connected in series relation across a portion of said source, the pair of brushes in alinement with the cross-field winding connected across a portion of said source, and the pair of brushes in alinement with the main field-Winding connected together through a" current-limiting device.

4. The combination with a source of alternating current, of a dynamo-electric machine of the inducing-field, commutator type, having an exciting field winding, variable speed driving means therefor, a multiplicity of peripherally spaced brushes bearing on the commutator cylinder thereof, and\ connections whereby the exciting and inducing field windings of said machine may be connected in series relation across a portion of said source, a plurality of brushes in substantial alinement with the inducing-field winding connected across a portion of-said source, and a plurality of brushes in subs stantial alinement with the exciting field winding connecting together through a current-limiting device.

5. The method of operating a singlephase, alternatingcurrent motor of the cross-field commutator type provided with pairs of brushes substantially in line with the exciting and cross field windings, respectively, which comprises connecting said motor for repulsion operation at starting, changing to a doubly-fed connection at higher speeds, and finally interconnecting the brushes in line with the exciting field stator winding for the production of the exciting field within the armature winding and eliminating the exciting field stator winding.

6. The method of securing a suitable exciting field for generating action in a dynamo-electric machine o fthe single phase, in

- RUDOLF E. HELLMUND. 

